Waveguide power dividing elements



Nov. 16, 1965 ZANICHKOWSKY WAVEGUIDE POWER DIVIDING ELEMENTS Filed Sept. 12, 1965 o ooooooo lNyENTOR. MART/N Zmv/cHKowsKv I 1- ATTIRNEY United States Patent 3,218,580 WAVEGUIDE POWER DIVIDING ELEMENTS Martin Zanichkowsky, 6 Gulls Cove, Plandome Manor, N.Y. Filed Sept. 12, 1%3, Ser. No. 308,534 3 Claims. (Cl. 3339) This invention relates to waveguides for ultra-high frequency or microwave transmission and more particularly to waveguide power dividers. It is especially useful for channelling a signal from a single input waveguide to a plurality of output waveguides in which any desired relationship of power levels may be obtained. Conversely, the power divider element may be used to combine the signals from a plurality of input waveguides into a single output waveguide.

In the waveguide art it is often necessary to channel the signal from a generator to a plurality of energy receivers such as radiating antennas or the like. Systems for accomplishing these functions are known in the prior art. Thus, one system employs waveguide T-branches to obtain the necessary power division. While these achieve the desired objectives, such T-branches are cumbersome in that they require considerable space since the incoming power can only be divided into two paths at one time. Such systems are also expensive. Another system employs a series of resonant structures with a tuned cavity to couple to each of the output waveguides. This is known as a serpentine feed, and is likewise cumbersome. Moreover, it is sensitive to frequency variations and requires tuning for each output waveguide.

It is, accordingly, the object of this invention to provide an improved, new type waveguide power divider for channelling an electromagnetic wave to a plurality of energy receivers such as radiating antennas and the like.

In carrying out the present invention there is provided a waveguide element having sidewalls and a top and a bottom wall, the latter two walls flaring away from each other in the fashion of a horn while the sidewalls remain parallel to each other. A plurality of power dividing walls are located between the top and the bottom walls of the waveguide element, the number of walls depending on the number of outputs into which the incoming electromagnetic wave is to be divided. The arrangement is further characterized in that each waveguide channel at the output end of the element is provided with a dielectric vane which can be adjustably positioned to select a desired phase shift in the electromagnetic wave carried by that channel.

A feature of the improved power divider is that it simultaneously effects as many power divisions as desired.

Another feature of the power divider is that it requires no tuning and it retains its power dividing accuracy over the complete waveguide frequency band.

Further features of the power divider are that it is compact, it can handle high peak power, and it has a low insertion loss.

Still another feature of the power divider is that the power level for each output channel can be arbitrarily chosen and accurately predetermined during manufacture so that no further adjustment is required.

Other features of the power divider are that it is well matched in R.F. impedance and that the output impedance for each channel can be the same as the impedance for the input channel or it can be fixed arbitrarily for particular applications.

A further feature of the improved power divider is that the output power for each channel can be adjusted in phase to yield a desired field pattern and the waveguide element of the present invention can receive return sig- "ice nals from a multiplicity of antenna elements and combine them without mutual coupling.

Other features and advantages of the present invention may be gained from the foregoing and the description of a preferred embodiment thereof which follows.

In the drawing:

FIG. 1 is a front sectional view taken through the waveguide element of the present invention;

FIG. 2 is a side elevational view taken at the input end of the element; and

FIG. 3 is a side elevational view taken at the output end of the element.

Referring to the drawing, the power divider waveguide element is shown by the reference numeral 10. At the input end of the power divider element, a flange 11 is provided to facilitate connection of the element to other waveguide sections leading from the energy source. The connection may be made by bolts extending through the openings 12 formed in flange 11 for this purpose. Of course, other suitable fittings could be provided for connecting element to preceding waveguide sections. The top wall 13 of element 10 and the bottom wall 14 flare and diverge from each other as clearly shown in FIG. 1. The divergence of walls 13 and 14 takes place in the direction of the electric field lines while sidewalls 15 and 16 remain parallel thus, in effect, forming a sectorial electromagnetic horn.

A plurality of power dividing walls 20 to 34 are provided within element 10 and they extend from sidewall to sidewall thereof. The number of such walls depends on the number of channels into which the input energy is to be divided. In the drawing, fifteen walls are illustrated for dividing the input wave into sixteen channels. If only seven output channels are desired, six walls would be formed in element 16. However, once this number is determined, and the relative power to be carried by each channel is determined, the design of the horn becomes fixed and the element cannot then be modified to accommodate a different number of output channels or a different division of power between channels. It will be observed in the embodiment shown that the dimensions of each output channel 35 to are the same as those of input channel 19. Thus the characteristics of the electromagnetic wave emanating from each output channel will have the same impedance as that of the input wave to channel 19 but vary as to power lever which will depend on the power division within element 10. If desired, the impedance of each output channel can be made different by varying the spacing between the walls 20 to 34. The initial power split, that is, the split effected by wall 20, should be delayed to the point where the effec tive waveguide height is similar to that of the incoming waveguide section. In this manner peak power capacity is maintained. Moreover, the power is split in the same ratio as the effective height of the guide is divided by the wall Ztl. The drawing illustrates the case where the power is divided approximately fifty-fifty. If the power were to be divided in the ratio of one to two with the smaller amount of power being transferred to that portion of element 10 located above wall 20, then distance a would be one-half of distance b. Of course, the power transmitted above wall 20 can similarly be divided in any ratio by the proper positioning of wall 21. Similarly, the power transmitted above wall 21 can be divided into any desired ratio by the selective positioning of wall 22. In the same manner, the power to be transmitted to each of channels 43 to 50 is determined by the location of walls 28 to 34. Where the term wall has been used to define the ratio of the split power, it is to be understood that it is the position of the leading edge of the wall that determines the ratio of the power split. As was previously noted, the incoming power can be split into as many channels as 3 desired and the ratio of the power carried by each channel can likewise be selected as desired.

The distance c between leading edges of the power dividing walls will generally exceed three-eighths of the wavelength of the electromagnetic waves carried by the waveguide in order to avoid mutual coupling between discontinuity susceptances and the consequent loss of power division accuracy and efiicieny of transmission. It will also be observed that the leading edge of each power dividing wall is triangular in section and the the sides of each triangle are substantially parallel to the next adjoining wall and the top or bottom wall of the waveguide element as the case may be.

A dielectric vane 51 is adjustably mounted on a pin 52 to effect a phase shift in the output power of channel 35, the degree of shift depending on the position of the vane. Once determined, the position of the vane is fixed. A similar vane may be placed in each of the output channels and the degree of phase shift in each channel individually determined. Of course, if a phase shift is not desired in a particular channel, no vane would be provided therein.

The output or terminating end of waveguide element 10 is, like the input end, provided with a flange 53 by which element 10 can be connected to other waveguide sections. As with flange 11 a plurality of holes 54 are provided so that element 10 can be bolted to the other waveguide sections. In addition, the end of each power dividing wall is provided with a slot 55. Corresponding prongs are provided on the waveguides connected to this end of the power divider element and these are fitted into the slots to insure the desired alignment between the channels 35 to 50 of element 10 and the waveguides connected thereto. Other suitable fittings can be provided for connecting and aligning element 10 to succeeding Waveguide sectrons.

Having thus described the invention it is to be understood that many changes can be made to the preferred embodiment disclosed without departing from the spirit and scope of the invention, and, therefore, the description and drawing are to be interpreted in an illustrative rather than a limiting sense.

What is claimed is:

1. A power splitting waveguide for dividing an incoming microwave signal into a plurality of channelized signals, said waveguide having a signal input end and a signal output end and comprising, a pair of parallel sidewalls each having a generally triangular shape, a top wall and a bottom wall that diverge from each other in the E- plane of the Waveguide, a first power dividing wall extending between the aforesaid sidewalls from the signal input end to the signal output end of said waveguide, a second power dividing wall extending between the aforesaid sidewalls and from behind the power dividing edge of said first wall to the signal output end of said waveguide, and a series of power dividing walls for successively dividing the microwave signal transmitted to the power dividing edges of each wall, each such power dividing wall extending between the sidewalls of said waveguide and from behind the power dividing edge of a preceding power dividing wall to the signal output end of said waveguide, and the power dividing edge of a power dividing wall being spaced from the power dividing edge of the immediately preceding power dividing wall by a distance slightly exceeding three eighths of a wavelength of the microwave transmitted through the waveguide.

2. A waveguide according to claim 1 wherein the output impedance of each channel formed by the power dividing walls is equal to the input impedance to the waveguide, and including a dielectric vane adjustably mounted in at least one of the aforesaid channels whereby a phase shift may be introduced to the signal carried by said channel.

3. A waveguide according to claim 1 wherein the output impedance of each channel formed by the power dividing walls is equal to the input impedance to the waveguide, and wherein the number of power dividing sidewalls is equal to the number of waveguide channels minus one.

References Cited by the Examiner UNITED STATES PATENTS 2,692,336 10/1954 Kock 343786 2,718,592 7/ 1955 Smith 343786 2,743,440 4/ 1956 Riblet 343--786 3,122,711 2/ 1964 Heninger 3339 FOREIGN PATENTS 204,607 8/1959 Austria.

0 HERMAN KARL SAALBACH, Primary Examiner. 

1. A POWER SPLITTING WAVEGUIDE FOR DIVIDING AN INCOMING MICROWAVE SIGNAL INTO A PLURALITY OF CHANNELIZED SIGNALS, SAID WAVEGUIDE HAVING A SIGNAL INPUT END AND A SIGNAL OUTPUT END AND COMPRISING, A PAIR OF PARALLEL SIDEWALLS EACH HAVING A GENERALLY TRIANGULAR SHAPE, A TOP WALL AND A BOTTOM WALL THAT DIVERGE FROM EACH OTHER IN THE EPLANE OF THE WAVEGUIDE, A FIRST POWER DIVIDING WALL EXTENDING BETWEEN THE AFORESAID SIDEWALLS FROM THE SIGNAL INPUT END TO THE SIGNAL OUTPUT END OF SAID WAVEGUIDE, A SECOND POWER DIVIDING WALL EXTENDING BETWEEN THE AFORESAID SIDEWALLS AND FROM BEHIND THE POWER DIVIDING EDGE OF SAID FIRST WALL TO THE SIGNAL OUTPUT END OF SAID WAVEGUIDE, AND A SERIES OF POWER DIVIDING WALLS FOR SUCCESSIVELY DIVIDING THE MICROWAVE SIGNAL TRANSMITTED TO THE POWER DIVIDING EDGES OF EACH WALL, EACH SUCH POWER DIVIDING WALL EXTENDING BETWEEN THE SIDEWALLS OF SAID WAVEGUIDE AND FROM BEHIND THE POWER DIVIDING EDGE OF A PRECEDING POWER DIVIDING WALL TO THE SIGNAL OUTPUT END OF SAID WAVEGUIDE, AND THE POWER DIVIDING EDGE OF A POWER DIVIDING WALL BEING SPACED FROM THE POWER DIVIDING EDGE OF THE IMMEDIATELY PRECEDING POWER DIVIDING WALL BY DISTANCE SLIGHTLY EXCEEDING THREE EIGHTS OF A WAVELENGTH OF THE MICROWAVE TRANSMITTED THROUGH THE WAVEGUIDE. 